Canonical variational transition-state comparative study for M⁺( = Li⁺, Na⁺and K⁺) + H₂O → [m·(H₂O)]⁺association reactions

The Canonical variational transition-state theory (CVTST) has been used in order to study the association reactions of three alkali-metal ions (Li+, Na+, K+) with a water molecule. Generalized transition states (GTS) are obtained by finding the maxima in the free enthalpy along the reaction path in the complete analytic potential-energy surfaces which include all inter- and intra-molecular geometrical parameters. The differences in the positions and energies of the GTS for the three reactions are observed to result mainly from differences in the entropic term -TΔS. The effect of temperature on these reactions is explained by carefully analysing the slopes for enthalpic ΔH and entropic -TΔS profiles along the reaction coordinate.